1. Field of the Invention
The invention is directed to a hold-down device for plate shears, which can be pressed on a plate, to be cut by a mechanically controlled, invariable displacement.
2. Description of Prior Art
hold-down device presses on the lower shear table while the plate is being cut. The hold-down device should be free of the plate while the plate is being transported. In particular, the operating cycle compresses: forward transport, safety angle, cut, safety angle, forward transport.
In practice, the hold-down device must usually cover the entire range of thickness of the plate from about 5 mm to about 50 mm. This requires a large displacement of the hold-down device. The design of the hold-down device is oriented to the thinnest plate in order to achieve the necessary contact pressing force. Its constant displacement is compensated for in spring sets. Consequently, the contact pressing force increases as the thickness of the plate increases. Thicker plates require less contact pressing force, or none at all, because of their greater inherent weight. The running of the hold-down device is continuous owing to its mechanical coupling and its displacement cannot be varied.
DE 35 46 859 C2 discloses a hold-down device for plate shears which is movable with a constant displacement by means of articulated levers.